.\" Copyright (c) 2011 Kai Wang
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.\" $Id: dwarf_get_arange_info.3 3962 2022-03-12 15:56:10Z jkoshy $
.\"
.Dd April 16, 2011
.Dt DWARF_GET_ARANGE_INFO 3
.Os
.Sh NAME
.Nm dwarf_get_arange_info
.Nd extract address range information from a descriptor
.Sh LIBRARY
.Lb libdwarf
.Sh SYNOPSIS
.In libdwarf.h
.Ft int
.Fo dwarf_get_arange_info
.Fa "Dwarf_Arange ar"
.Fa "Dwarf_Addr *start"
.Fa "Dwarf_Unsigned *length"
.Fa "Dwarf_Off *cu_die_offset"
.Fa "Dwarf_Error *err"
.Fc
.Sh DESCRIPTION
Function
.Fn dwarf_get_arange_info
extracts address range information from a
.Vt Dwarf_Arange
descriptor.
.Pp
Argument
.Fa ar
should reference a valid
.Vt Dwarf_Arange
descriptor returned by function
.Xr dwarf_get_aranges 3 .
.Pp
Argument
.Fa start
should point to a location which will hold the start value of the
address range associated with the descriptor.
.Pp
Argument
.Fa length
should point to a location which will hold the length in bytes of the
address range associated with the descriptor.
.Pp
Argument
.Fa cu_die_offset
should point to a location which will be set to an offset, relative to
the
.Dq ".debug_info"
section, of the first debugging information entry in the compilation
unit associated with argument
.Fa ar .
.Pp
If argument
.Fa err
is not
.Dv NULL ,
it will be used to store error information in case of an error.
.Sh RETURN VALUES
Function
.Fn dwarf_get_arange_info
returns
.Dv DW_DLV_OK
when it succeeds.
In case of an error, it returns
.Dv DW_DLV_ERROR
and sets the argument
.Fa err .
.Sh EXAMPLES
To loop through all the address lookup table entries, use:
.Bd -literal -offset indent
Dwarf_Debug dbg;
Dwarf_Addr start;
Dwarf_Arange *aranges;
Dwarf_Off die_off;
Dwarf_Signed i, cnt;
Dwarf_Unsigned length;
Dwarf_Error de;

if (dwarf_get_aranges(dbg, &aranges, &cnt, &de) != DW_DLV_OK)
	errx(EXIT_FAILURE, "dwarf_get_aranges: %s",
	    dwarf_errmsg(de));
for (i = 0; i < cnt; i++) {
	if (dwarf_get_arange_info(aranges[i], &start, &length,
	    &die_off, &de) != DW_DLV_OK) {
		warnx("dwarf_get_arange_info: %s",
		    dwarf_errmsg(de));
		continue;
	}
	/* Do something with the returned information. */
}
.Ed
.Sh ERRORS
Function
.Fn dwarf_get_arange_info
can fail with:
.Bl -tag -width ".Bq Er DW_DLE_ARGUMENT"
.It Bq Er DW_DLE_ARGUMENT
One of the arguments
.Fa ar ,
.Fa start ,
.Fa length
or
.Fa cu_die_offset
was
.Dv NULL .
.El
.Sh SEE ALSO
.Xr dwarf 3 ,
.Xr dwarf_get_arange 3 ,
.Xr dwarf_get_arange_cu_header_offset 3 ,
.Xr dwarf_get_aranges 3 ,
.Xr dwarf_get_cu_die_offset 3
